Electron discharge device



p 1943 L. s. NERGAARD ELECTRON DISCHARGE DEVICE Filed Oct. .30, 1941 2 Sheets-Sheet 1 INVEN o;

.fi fl%w ATTORNEY Sept. 21, 1943. L s. NERGAARD 2,329,778

ELECTRON DISCHARGE DEVICE Filed Oct. 30, 1941 2 Sheets-Sheet 2 'I'IIIIIIIIIIIIIIIIII wfl au/ ATTORNEY Patented Sept. 21, 1943 Leon S. Nergaard,verona, N. It, assignortoRadio fl Corporation ofAmerica, a corporation of Dela- V ware r Application Qctober 30, 1941, Serial No. 417,122

My invention relates to electron dischargede vices, more particularly to such'devicesuseful at ultra high frequencies. a a

It is desirabl'eto have an output system having low impedance suitable for operation with broad band circuits in the ultra high frequency field and to have an electron discharge'device Whichmay be incorporated in such a system. It is further desirable to eliminate high frequency losses nor;-

mally encountered in "bringing high frequency leads through the envelope of the, electrondis-' charge devic'e. Another desirableffeature is to be able to separate electrically and physiallythe output electrodes from the current'collector' so that the power dissipating ability of the"output 15 end an'indirectly heated cathodel l provided with electrodes imposes no limitation onthepowezfi aheaterl i. .A grid 9 may beprovidedladjacent s output. H thecathode either for modulation-purposes or :as It is, therefore, an object of my invention to a space charge grid. This 'grid its-provided with provide an electron discharge device suitable for i an extended collar 9' closely adjacent the tube use at high frequencies and capable of-u's'e with 20 Wall-Jfor" pur o s to be des ribedn Mounted at outputsysterns having a low output impedance the other end of'the envelopeisaarcollector l2 and suitable for operation with broad band for collecting-electrons inzthe beam supplied by circuits. 4 the cathode 1H. ..Positioned a1on'g:theenvelope j It'lS another object of my invention to provide are a .pair of accelerating: and screen electrodes an electron discharge device suitablefor'use at 25 J3, and M. having appliedlthereto proper voltages high frequencies and which avoids the use ofhigh frequency leads extending through the tube 'velope, thus reducing high frequency lossesgj Another object of my invention is to separate the current collector and output electrodes so that the'power dissipating-ability of the electrodes acteristic of myinvention-are set forth with particularity in the appended claims, but the inventioir itself Will best be-understood by reference tothe following description taken in connection v with the accompanying drawings in which t Figure l is a schematiclongitudinal section of an electron discharge device' and associated circuit made according to my invention, Figure 2-is a transverse-section taken along line 2 2 of Figure'1, and Figure 3 is'a longitudinalschematic showing of a modification ofthe device shown in As shown in the drawings in Figures land 2, e

an elongated envelope it has positioned-at one for maintainingthe neighboring :space at apoltential high enough to .prevent reflection of elecimposes no limitation on the power output. I hese and other objects will appear hereinafter. 7

Recently there has been developed whathas been termed velocity modulation for use at ultra high frequencies. Inthe arrangements proposed the electrons of an electron beam'or stream are given varying velocities, the'variation invelocity being applied cyclically so'that the beamcom? prises slow and fast electrons. As a result atpre determined points the fast electrons overtake the slow electrons, producing groups or bunching;

' When groups have been bunched it ispossibl} to extract energy from the beam by proper electrode arrangements either inductively or by absorption Y by absorption electrodes; This method of producing slow and fast electrons inv abeai n has proved particularly useful at ultra high fre quencies. v v

It is, therefore; another object of my invention to provide an improved electron discharge device trons and" to acceleratethefelectrons downalong .the length o-frthettube. wAsuppressor andrscreen -l 5is positioned adjacent the collector l 2'. A tank circuitiis provided surrounding the envelope 7 witha resonantmcavityhtankicircuitl6 provided with aslotiolfgap ll surrounding: the discharge path' between the accelerating electrodes; l 3' and rlfiuThe edges of thecavityincludeapair of electrodes merged into the cavity, TheQR-F. field generated across the. gap during operation of the deviceresults in velocity modulation of the, 1ectron m- T i ta ircuit ma b used. a

I in input circuit underjcertain conditions or a a zl ce io eill Circuit u der oth ndi ions s will be described, i

1 The output electrodes comprise. apair o fan} ode segments l5320 surrounding the outside of I :thgflubeenvelope and connectedto the conducrs 2| forming part of a transmissmnline tank :circ'uitQ A rod 2. m ne d r 9136mm at. substantially cathode "potential serves. to pro- ,vi de' an outwardl lc'lirected radial "electrostatic field This fieldin combinationwith 'a longitu dinfalmagnetlcfieldfcausesithe electrons to pass utilizing velocity modulation and particularly such a device utilizing the desirable characteristics of a-magnetron.

A still further object of my invention is to pro vide an electron discharge device suitablefor use g at high frequencies,particularly such' 'a device pable of use as a mixer in superheterodynereception at high frequencies; I

"close to the tube envelope walllwhe'nthe' appara tus' is in operation, the electrode. IE -acting" as a l suppressorand screen. The rod 22 also serves to reduce the axialiflongitudinal velocityfof the electron str amasja whjo ie, 'Theoutput circuit is completed by means ofa'IshOrting bar or disc 2!" slidable on the conductors 2| and contactingitheshielding comp-artmentfison the intefriorto'completely shieldthe output electrodes The electron discharge device just described is also particularly suitable for use as a mixer when superheterodyne reception is employed. When so used, a Lecher wire system comprising the conductors 3i! and shorting bar 3i are connectedbetween the cathode H and grid 9, the input signal being coupled to the Lecher wire system by means of the loop 32. The cathode is coupled to one of the Lecher wire conductors byv means of the capacity 34 Thus it is possible to introducethe input signal by means of the Lecher wire system and the local oscillator volt age by meansof the coupling loo-p l6 and tank iii, the intermediate frequency being extracted by the output circuit comprising conductors 2| and shorting disc 2| coupled to the loop 24. When it is not desired to introduce a signal on the grid and to use the grid merely as a focusing grid, the shorting bar may be removed or moved close to the tube envelope. V 1

When operated with no R.-F. signal on the grid-the electron stream is focused by the ,grid- 9 and accelerated by electrode [3, these two electrodes being maintained at the same RAF. potential by the .by-passing action of collar 9. con pied to the inner conductorof tankcircuit It to which electrode I3 is connected. In passing across gap i! of tank l6,.the stream of electrons is velocity modulated, after which the-electrons enter the output space through accelerating electrode M, which serves to maintain the neigh boring space at a potential high enough to pre vent reflection of electrons. The number .of spirals which the electrons performin moving axially through the output electrodes depends on the axial velocity. The output varies with the velocity modulation impressed on the beam-by the applied signal. In the space between the anode segments l9 and 20, the electrons perform spiral orbits,.as inmagnetrons, and give upa fraction or their energy to the output electrode segments 19 and 2t each time they cross the slot field of the output electrodes. The fast moving electrons take orbits having larger radii than'the slow moving electrons which follow by approximately 180 in phase. The fast electrons hence come closer to the gap field giving up more-energy than the slower electrons may absorb. The time of one orbit may be matched to a period of the input frequency to provide proper phase relationship between input and output. The effective current from which the output electrodes obtain power is thus the product of beam current and the number of spirals. Since this effective current is large, the tubeis capable of driving a low impedance load, such as encountered in wideband transmission. After giving up their energy, the electrons are collected by. a' collector electrode l2. V

The input voltage to drive the input tank circuit [6 is fed to the tank circuit by means of the coupling loop [6, and the output voltage is taken from the output circuit 2| through the loop 24, the output circuit being tunable by means of shortingdisc 2i sliding between the shielding compartment. having extension 23 longitudinally of the envelope and shielding the suppressor i5 and collector l2. 7 I

When used for superheterodyne reception an input signal is applied to the Lecher wire system '36 and thus the. electrons are modulated by grid 9, the modulated stream being accelerated by electrode l3 and velocity modulated with the oscillator voltage at gap [1. The intermediate frequency voltage is extracted by means of the electrodes l9 and 20 and the intermediate frequency taken from the circuit 2| and 21' by means of the loop 24. I

In Figure 3 the same numerals indicate the same elements as in Figures I and 2. However, in this modification the resonant cavity tank circuit is provided. with a pair of tubular electrodes 30-41 electrically connected to the tank circuit on opposite sides of the gap, the electrode 30 being provided with the rod 32. The wire tween 3|ar'1d 32. This field varies in strength with the applied'signal. Therefore, as the beam formed by the cathode and grid passes through the mem em it receives a radial component of velocit'y'proporitional to the signals. The "tubular electrodes i5, 30 and 3| are operated at suificiently high potentials to prevent electron reflection. When theelectrons pass through the output space the'yperform spirals whose radii depend on the magnetic field strength, the potential of the output electrodes, and the radial velocity of the electrons as they enter the space. The electrons having the greater radial velocity on entering. the output space will'approach the output electrodes moreqclosely than those entering. with lower radial velocity,. and will, therefore,

. beam. Again a large number of spirals is performed, hence the effective output current is large and. the tube can operatewitha broadband circuit. i w In connection with electrodes BOP-3i and rod Q2, when the fieldacrossgap H is an accelerating field,..su'ch thatelectrons are accelerated across thegap, rod SjZisat. a lower potential than the electrode 3| and theradial'field is outward causing the fast moving electrons to move outwardly closer to the inner wall of the tube envelope. On the other hand if the electrons in passing across the gap are subjected to a retarding field, thus reducing the velocity of the electrons, the rod 28 is at a more positive potential and there is a tendency to dr aw the slow moving electrons in close to the axis of thetube, Thus the fast and slow electrons are not only separated axially along the tube but also radially, the fastermoving electrons approaching more closely the tube wall and thus delivering greater energy to the anode; segments. p 7 l l While I have indicated the preferred embodiments of my invention of which I am now aware and have also indicated only one specific application for which my invention may bee-mployed, it will be apparent that my invention is by no means limited tethe exact forms illustrated or the use indicated, but that many variations may be made in the particular structure used and the purpose for which it is employed without departing from the scope of my invention asset forth in the appendedclaims. a

What claim as new is:

1. Anelectron discharge device having means for supplying a beam of electrons; meansfor' velocity modulating said beam of electrons and an electrode for receiving electrons in, said beam, output electrode means positioned betweensaid velocity modulating means and the receiving electrode and comprising a plurality "of Segments surrounding the path of the beamand provided With-gaps between said segments," means includeing a rod within and coaxialwith saidsegments and magnetic means for causing electronsoi said velocity modulated beam tofollow spiral orbital paths within the output electrode means a'plu': rality of times past the gaps between the plurality of segments and then towardpthe' receiving electrode; I" 2. ;An electron discharge device having means forsupplying a beam of electrons, an electrode for receivingelectrons in said beam,ioutputfelec-" trode'means including a' pluralityof electrode segments surroundinglthe, path of thejbeam and; separated by gaps exteriding falong the axis of said beam, means positioned'between the. beam supplying means and the output electrodemeans,

including electrodes surrounding the path'of said beam and spaced by a gap lying in a; plane trah's-' verse to the path of the beam,;]and means'for including electrodes surrounding said beam and spaced by a gap lying in a plane transverse to the path of the beam, means for causing electrons to follow orbital paths through said output elece trode means including means for p'roducingfa magnetic field along the axis or said electrondis'; charge device, and a rod positioned coaxially or said output electrode means and adapted to 'be maintained at cathode potential during operation of said electron discharge'device, a conductor connected to one of said electrode segments and another conductor connected to another electrode segment, and means electrically connecting said conductors together remotefromsaid segments to provide an output circuit. v

4. An electron discharge device having means for supplying a beam of electrons, an electrode for receiving electrons in said beam,output electrode means including a plurality of"electrode said electron discharge I segments surrounding the path of the beam and separated by gaps extending along the axis of said beam, means positioned between ,the beam supplying means and the output electrodemeans, including electrodes surrounding said beam and spaced by a 'gap lying in a plane transverse to the path of the beam, a resonator surrounding said path, said last electrodes beingelectricallyconnected to said resonator, means for causing elec trons to follow orbital paths through said out: put 'electrode means and including means for producing'-amagnetic field along theaxis of said electron discharge device, and a rodpositioned coaxially of said output electrode means'and adapted to bemaintained at cathode-potential during operation of said'ele'ctron discharge device, a conductor connected to one of said electrode segments and another'conductor connected to another electrode segment, and means 616C: tricall'y connecting said conductors together remote from said segments toprovide an output circuit, and shielding means surrounding said output electrodes and said conductors.

5. An electron discharge device having'an elon gated envelope and containing a cathode'for pro-.

viding a stream of electrons; and a collector for collecting said electrons, a resonator surrounding said envelope'and provided with a gap surround-- ing said envelopeladjacent said cathode, for providing. a radio frequency field for velocity m0dulating the electrons from said cathode,"*a pair of accelerating and screen electrodes within said envelope and positioned on opposite sides ofsaid gap, an output electrode system positioned between: said: velocity modulating resonator and said collector, andhaving electrcdesegments surrounding said envelope, said segments being spaced by gaps extending along said "envelope, and means for causing the electrons to follow orbital paths through said output electrode system andincluding means for producing an gleetromagnetic field within said output electrode system and parallel to the longitudinal axis of said envelope, and a rod electrode positioned axially within said electrode segments and adapted to be maintained at cathode potential during op eration of said electron discharge device, and a conductor connected to one of saidelectrode segmentsand a second conductor connected to another electrode segment and parallel to the other conductor, and meansconnecting said conductors together remote from said segmentsfor providing an output transmission line'circuit and a shield surrounding said output electrode system and said conductors, I

- 6. Anelectron discharge device havingan elo'ngated envelopeandcontaining a cathode for providing a streamof electrons, and a collector for collecting'said electrons, a resonator surrounding said envelope and provided with a gap surrounding said envelope adjacent said cathodeifo-r'providing a radio frequency field forvelocity modu I lating" the electronsfrom said cathode, an output electrode system positioned between saidresonator and said collector, and having electrode segments surrounding said envelope, said seg-' ments beingspaced'b-y gaps extending along said envelope, and means for causing the electrons to follow orbital paths through said output. electrode system'and including means for producing an electromagnetic field within'said output electrode system and parallel to the longitudinal axis of said envelope. I I

- 7. An electron discharge device having an elongated envelope and containing a cathode for providing a stream of electrons, anda collector for collecting said electrons; a resonator surrounding said envelope and provided with a gap surrounding said envelope adjacent'said'cathode'for pro-.

viding aradio. frequency field for velocity modulating the electrons fromsaid cathode, a pair of accelerating and screen electrodes Within said envelope and positioned 'onopposite sides of said gap, an output'electro'de system positioned be tween said velocity modulating resonator and said collector, and having electrode segments surrounding said envelope, said segments being and means for causing the electrons to. follow orbital paths, through saidoutput electrode system and including means forproducing an electromagnetic field within said output electrode systern and parallel to thelongitudinal axisoi said envelope. I

8. An electron discharge device having an elongated envelope and containing a. cathode for providing a. stream of electrons, and acollector for collecting saidelectrons, a. resonator surrounding saidenvelope and providedwith. a gap surroundingsaid envelope: adjacent said cathode for providing a radio frequency field. for velocity modulating the electrons from; said; cathode, a pair of accelerating'and screen elec-' trodes Within said envelope; and positioned on, opposite sides of said gap, an output electrode system positioned between. said velocity modulating resonator and said collector, and having electrode segments surrounding said envelope; said segments being spaced by gaps extending. along said envelope, and means for causing the electrons to follow orbital paths through said: output electrode system and. including means: for producing an electromagnetic field within. said output electrode system and parallel: to the: longitudinal axis of said envelope, and a rod electrode positioned axially within said electrode: segments and adapted to be maintained at oath-- ode potential during operation of said electron discharge device. 1

9; An electron discharge device having an: elongated envelope and containing a cathode for; providing a stream of electrons; and: a collector for collecting said electrons, a resonator; sur rounding said envelope and provided With".2Ag-EII surrounding said envelope" adjacent said cathode for providing a radio frequency field for velociizv modulating the electrons from said cathode, a pair of accelerating and screen electrodesawithin said envelope and positioned on opposite. sides of said gap, an output electrode system positioned between said: velocity modulating resonator and said collector, and. having electrode. segments surrounding said envelope, saidsagments being spaced by gaps extending alongsaid envelope, and means for causing the electrons to follow orbital paths through said; output electrode system and including means for producing an electromagnetic field within; said output-electrode system and parallel to the longitudinal-axis of said envelope, and a, first conductor con.- nected to one of said, electrode segmentaand a, second conductor connected, to another electrode segment and parallel to the first conductor, and means connecting said conductors together. re,- mote from said segments providing an. output transmission line circuit and a shield; SllIJIOllIld-r ing said output electrode system and said conductors.

10. An electron discharge device having an elongated envelope and containing acathode for. providing a stream of electrons, and a collector for collecting said: electrons, a: resonator surrounding said envelope and provided with, a gap surrounding said envelope adjacent said cathode; a, pair of electrodes Within said envelope and connected to. said resonator on opposite sides of said gap for providing aradio: frequencyfield therebetween for velocity modulatingtheelectrons from said cathode, andia rod-electrode extending. axially of one said; accelerating electrodes and electrically connected tolthe otherofi said electrodes and an output electrode system positioned" between said resonator and said, col

lector, and having electrode segments surrounding said envelope, said segments being spaced by gaps extending along said envelope, and means for causing the electrons to follow orbital paths. through saidelectrode system and including means for producing an electromagnetic field within said output electrode? system and parallel to the longitudinal axis of said envelope.

11. electron discha-rge device having an elongated envelope and containing a cathode for providing-a. stream of electrons, and a collector for collecting said electrons, a resonator sur-r rounding said envelope and provided with. a gap surrounding said envelope adjacent said cathode, a. pair oi electrodes within said envelope and connected. to said resonator on opposite sides 05 said gap tor providing a radio ,{frequency field therebetweeril for velocity modulating the electrons from said cathode, and a rod-electrodes tending. axially of one of said electrodeszandpelectrically connected. to the other of said electrodes and -an, output electrode system positioned be-- tween said'velocity modulating resonator and said collector, and having-electrode segments surrounding said envelope, said segments being spaced. by gapsextending along said envelope, and screen and accelerating electrodes positionedion opposite sidesof said output electrode system,jand. means for causing the electrons to: follow orbital: pathsthrough said output elec-- trode. system and includingmeans for producing an electromagnetic field within. said output electrode. system. and parallel to the longitudinal axis of. said envelope,- and a rod electrode positinned axially within said electrode segments and adapted to be maintained at cathode potential during. operation. of said electron discharge d'evi'ce..

121An electron discharge device having an elongated. envelope and containing a cathode for proidi'rig a stream of electrons, and a collector for collecting, said electrons, a resonator surrounding, said envelope and provided with a gap surrounding said envelope adjacent. said cathode,

- a pair of electrodes within'saidenvelope and connected to'said resonator on opposite sides of said gap for providing a radio frequency field therebetween. for velocity modulating the electrons from said cathode, and a rod-electrode extending axially of one of said electrodes and electrically connected toft'he other of said' electrodesandan output electrode system positioned between said velocity modulating, resonator and said collector,. and having electrode segments surrounding said envelope, said segments being spaced by. gaps-extending along said envelope, and means for causing the electrons to follow orbital. paths through said electrode system. and, including means forproducing, an electromagnetic field. within said output electrode system andparallel to thelongitudinal axis of said envelope, and a conductor connected. to one. of. said electrodesegments and a second conductor connected to another electrode. segment. and parallel to the other cond'uct'or, and. meansconnecting said conductors togetherremote from said segmentsproviding an. output transmission line circuit and a shield surrounding said. output. electrode system and saidconductors.

l3. A-nelectron discharge device having an elongated. envelope. and containing a cathode' forproviding astreami of electrons, and a collector for collectingpsai'd. electrons, a resonator surrounding. said; envelope and provided witha gap surrounding .said' envelope adj acent 1 said cathode,

apair of electrodes within said envelope and connected to said resonator on opposite sides of said gap for providing a radio frequency field therebetween for velocity modulating the electrons from said cathode, and a rod-electrode extending axially of one of said electrodes and electrically connected to the other of said electrodes and an output electrode system positioned between said resonator and saidcollector, and having electrode segments surrounding said envelope, said segments being spaced by gaps extending alongsaid envelope, and accelerating electrodes positioned on opposite sides of said output electrode system, and means for causing the electrons to follow orbital paths through said output electrode system and including means for producing an electromagnetic field within said output electrode system and parallel to the longitudinal axis of said envelope, and arod electrode positioned axially within said electrode segments and adapted to be maintained at cathode potential during operation of said electron discharge device, and a first conductor connected toone of said electrode segments and a second conductor connected to another electrode segment and parallel to the first conductor, and means con necting said conductors together remote from said electrode segments providing an output transmission line circuit anda'shield surrounding said output electrode system and said conductors.

14. An electron discharge device having a cathode for supplying a beam of electrons, an

providing a stream of electrons and a collector for collecting said electrons, an electrode adjacent the cathode -for modulatingthe stream of electrons from said cathode, a resonator surrounding said envelope and provided with a gap surrounding said envelope between said modulating electrode and said collector for providing a radio frequency field for velocity modulating the electrons from said cathode, an output eleclongitudinal axis of said envelope.

1 envelope, a resonator surrounding said envelope 17. An electron ,discharge device having an elongated envelope and containing a cathode for providing a stream of electrons and a collector for collecting said electrons, a grid adjacent the cathode for modulating the stream of electrons from said cathode and having an extended collar positioned closely adjacent the inner Wall of said and provided with a gap surrounding said envelope between saidmodulating grid and said collector for providing a radio frequency field for velocity modulating the electrons from said.

, cathode, a pair of screen and accelerating elecelectrode for receiving the electrons in the beam,

a first control electrode adjacent the cathode for modulating the electron stream, and a second electrode means surrounding the path of the electron stream adjacent the first control electrode and including electrodes surrounding said.

beam path and spaced by a gap lying in aplane transverse to the path of the beam, an output electrode means including a plurality of electrode segments surrounding the path of the beam and separated by gaps extending along thelongitudinal axis of said beam, and means for causing electrons to follow orbital paths through said output electrode means and including meansv for producing a magnetic field along the axis of said beam.

15. An electron discharge device having an elongated envelope and containing a cathode for providing a stream of electrons and a collector for collecting said electrons, an electrode adjacent the cathode for modulating the stream of I electrons from, said cathode, a resonator surrounding said envelope and provided with a gap surrounding said envelope between said modulating electrode and said collector for providing a radio frequency field for velocity modulating the electrons from said cathode, a pair of screen and accelerating electrodes within said envelope and positioned on opposite sides of said gap, an output electrode system provided between said resonator and said collector 'and having electrode segments surrounding said envelope, said segments being spaced by a gap along said envelope, and means for causing electrons to follow orbital paths within said output electrode system and including means for producing an electromagnetic field within said output electrode system and parallel to the longitudinal axis of said envelope.

16. An electron discharge device having an elongated envelope and containing a cathode for trodes within said envelope and positioned on opposite sides of said gap, saidresonator having an extended wall closely adjacent the tube envelope and surrounding the grid collar and one of the screen and accelerating electrodes, an output electrode system provided between said resonator and said collector and having electrode segments surrounding said envelope, said segments being spaced by a gap along said envelope, and means I for causing electrons to follow orbital paths within said output electrode system and including means for producing an electromagnetic field within said output electrode system and parallel to the longitudinal axis of said envelope.

18.An electron discharge device'having an 1 elongated envelope and containing a cathode for providing a stream of electrons and a collector for collecting said electrons, an electrode adjacent the cathode for modulating the stream of electrons from said cathode, a resonator surrounding saidlenvelope and provided with a gap surrounding said envelope between said modulating electrode and said collector forproviding a radio frequency field for velocity modulating the electrons from said cathode, a pair of screen,

and accelerating electrodes within said envelope and positioned on opposite sides of said gap, an output electrode system provided between said resonator and said collector and having electrode segments surrounding said envelope, said segments being spaced by a gap along said envelope,

and means for causing electrons to follow orbital paths within said output electrode system and including means for producing an electromagnetic field within said output electrode system and parallel to the longitudinal axis of said enve- I LEON S; NERGAARD. 

